1. Field of the Invention
The present invention relates to a feeding device for copiers, printers and the like.
2. Description of the Related Art
Conventional feeding devices for copiers and printer and the like have pick-up rollers for feeding the paper sheets and a handling section for handling the paper sheets disposed downstream from said pickup roller in the sheet transport direction. The handling section is known to be provided with a forward rotation roller that is rotatably driven in the same direction as the sheet transport direction, and a reverse rotation roller that is rotatably driven in the opposite direction to the sheet transport direction and which is in pressure contact with said forward rotation roller. The aforesaid handling section is constructed such that when the pickup roller feeds a plurality of sheets to the nip area between the forward rotation roller and the reverse rotation roller, only the uppermost sheet is fed thereto while a second and any subsequent sheets are returned by the reverse rotation roller. Typically, the sheet transport speed of the forward rotation roller is set so as to be greater than the sheet transport speed of the pickup roller.
In a feeding device of the aforesaid construction, a sensor for detecting the fed sheets is provided near the nip area of the forward rotation roller and the reverse rotation roller, such that when the insertion of a sheet into the nip area is detected, the pickup roller separates from said sheet. Thus, the pickup roller prevents deterioration caused by the friction generated between said roller and the sheet transported at the sheet transport speed by the forward rotation roller by means of the separation of said pickup roller from the sheet.
In a conventional feeding device such as described above, there is some anxiety that the pickup roller will separate from the sheet before said sheet is reliably inserted in the nip area formed by the forward rotation roller and the reverse rotation roller. When the pickup roller separates from a sheet before said sheet is reliably inserted in the aforesaid nip area, the sheet does not receive sufficient transport force from the pickup roller which results in improper feeding of the sheet.